Sealing and Insulation אדריכלות ישראלית Architecture of Israel # 126 August 2021 24 | | Building sealing and insulation is probably one of the most paradoxical subjects in architecture. While architecture aspires to stabilise buildings in the ground, sealing makes every effort to isolate it from the ground. This, due to the fact that while water is considered the "source of life”, it is one of the most destructive factors in buildings. Disconnecting structures from the ground is affected naturally by environmental conditions such as the type of the soil, topography and outside forces such as rain, winds and land fluctuations. Accordingly, the selection of sealing means has to be suited to the type of structure, its purpose and function. Although the importance of the insulation measures are essential to the durability of the structure and its capacity to survive in the long term, from the architectural point of view they are considered the “black”, hidden area of the building. This, while "wisdom of the architecture" is mainly featured by visible details such as roofs, gutters, folds and toppings. This creates a situation where most architects are not aware of the importance of sealing, not to mention its influence on the architectural visibility. Officially, most sealing and insulation methods are detailed in several standards and regulations, including the specifications that one can find in the 'Blue Book' and in Israel Standard 1430, and other standards regarding roof sealing, preparation of surfaces before building, and aspects of thermal isolation. In this inadequate reality, Israel Standard 2752 is in its advanced stage of preparation, and once its nine parts are completed it will mandatory in most construction in Israel. The Standard primarily refers to the type of structures, the nature of ground, weather conditions, and above all the building purpose that would determine its sealing method. Under the new Standard, buildings are divided into several sub-groups according sealing and insulation the invisible paradox of architecture Dr. Hillit Mazor to their required essential sealing: 'very highly essential', 'highly essential', or 'low essential'. Naturally, sealing the underground parts of a building is much more complicated than those above ground. Therefore, the second part of the Standard deals with planning the sealing methods of the building’s foundations, focusing on the methods and means to prevent rainwater penetration, by natural or artificial drainage. This, while the rest of the Standard mainly deals with planning the sealing methods of the above-ground parts, such as floors, walls and roofs - all of which are mainly affected by the need to protect the building from weather conditions. However, natural disasters in Israel, as well as in Europe and other places in the world, pose serious questions about all conventional methods of sealing and insulation. It has been proven in the painful lesson of extreme weather events that conventional drainage systems cannot handle massive and unexpected quantities of water. It is categorically proven that in contrast to the prevailing opinion that flooding occurs at the local level, the process begins at the regional level, overwhelming local drainage systems; and from there, penetrate to every part of the building. (see a detailed article about rainwater treatment in AI #124). As mentioned, the proposed 2752 Standard defines the accepted methods of removing rainwater from the building, particularly the basements. But thousands of flooded structures throughout the country indicate that the problem is much more complicated; it turns out that in times of emergency, nature does not distinguish between the parts of the building nor their defined sealing essentiality. Thanks to the development of composite materials (combination of preferred properties of several materials), technological developments, means of sensors and computerised monitoring, there has been significant progress in both the field of sealing materials and their applied methods. As a result, we are witnessing an improved and more efficient sealing and insulation method, assuring extended durability. Innovative sealing solutions are now integral to the concrete sealing technologies of crystallization, casting or injection of composite materials, Applied for several decades, such technologies meet international standards (American, German, British, Canadian). Special thanks to Eng. Eitan Haviv, for his professional advice. Built upon stone layers, traditional houses in Iceland are well attached to the ground, yet protected in case of floods.